Michael Mosley
On the surprising power of the placebo.
Normally, I don’t set out to mislead members of the public, particularly on behalf of the BBC. But I recently did so for Horizon, in order to explore an extraordinary phenomenon: the placebo effect. For this episode, we invited more than 100 people from Blackpool with chronic back pain to come to a medical centre and take part in an experiment. They were told they would either get a placebo, which was a pill containing ground rice, or they might get a novel painkiller. Or they might be offered nothing more than standard care (a control group). What we didn’t tell them is that all those receiving pills would be getting placebos.
When our volunteers arrived, they all got a physical examination and were asked to fill out a disability questionnaire, before seeing one of four GPs. Some of them received the standard GP consultation of nine minutes and 22 seconds, while others got nearly 20 minutes.
The study was designed by Dr Jeremy Howick, an expert on the placebo effect from the University of Oxford. He was keen to see the impact of the placebo on back pain, and also wanted to measure the effect of a longer GP consultation. There is a widespread belief that only the weak-willed or gullible succumb to the placebo effect, but Howick says this is not true. The main characteristic of people who respond to placebos is that they are open to new experiences. He also pointed out that just because a placebo contains no active chemicals, it doesn’t mean the effect is not real. Among other things, taking a placebo can trigger the release of endorphins – natural painkillers that are similar in structure to opioids like morphine.
Then there’s placebo surgery. A few years ago, surgeon Prof Andy Carr decided to examine the effectiveness of acromioplasty, an operation that involves removing a spur of bone from the shoulder to relieve pain and improve mobility. About 25,000 are performed every year in England and Wales. Carr wondered if it was the operation that was helping his patients, or the placebo effect. He did a trial in which volunteers were randomly selected to receive either real surgery; ‘fake surgery’ in which they were anaesthetised, cut open and sewn back up again; or physiotherapy. The patients who had an operation did better than those who had physiotherapy, but it made no difference whether it was a real operation or not. The NHS has since announced that it will no longer be offering acromioplasties. Patients will receive physio instead.
Back in Blackpool, after three weeks of swallowing pills, my volunteers went through another series of tests and questionnaires. Then it was time to reveal all. We discovered that nearly half of them had got significant pain relief from taking the pills, even though they were fake. The ones who did best were the ones who believed they were getting ‘real’ pills. And those getting the extra GP time had done almost twice as well as those who got the standard amount, which shows what a powerful effect a doctor’s time and attention can have. Only 20 per cent of the control group, by contrast, saw benefits. Perhaps the most surprising thing is that when I asked them if they would like to go on taking the pills for another few weeks, knowing they were placebos, most said yes.
So where does that leave modern medicine? A recent article in the British Medical Journal suggested that it can be ethical to prescribe placebos, as long as the doctor tells the patient that’s what they are doing. The article cites evidence that placebos can work even when the patients know that is what they are taking.
“PLACEBOS, EVEN THOUGH THEY’RE FAKE, OFFER REAL PAIN RELIEF”